JP4433492B2 - Data exchange method with programmable controller - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for exchanging data between an external data handling device such as a display device and a programmer controller.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, for example, in a display device controlled by a personal computer, as shown in FIG. 1, a plurality of device information of a programmable controller is used for one screen display operation (project), and several different contents are used. Display (object) is performed. When executing such a plurality of objects, conventionally, the device information required from the display device side to the programmable controller is requested for each object, and the device information corresponding to the request is received from the programmable controller. Returning to the display device, each time the communication is performed, the display application of the display device operates synchronously to perform a display operation.
[0003]
[Problems to be solved by the invention]
In the conventional communication method, since communication is performed for each object, in a project where there are a large number of objects, the system is very responsive. In addition, device information may be duplicated in a plurality of objects included in a project, and as a result, the same device information is communicated over and over, resulting in an increasingly poor response.
An object of the present invention is to provide a data communication system with a responsive programmable controller. It is another object of the present invention to provide a data communication method that can realize simple communication control in which the application on the project side can obtain device information completely asynchronously with the communication system.
[0004]
[Means for Solving the Problems]
In order to solve the above problems, in the present application, data is exchanged between a programmable controller and an external data handling device such as a display device, and device information is stored corresponding to the device number of the programmable controller. An intermediate memory is provided, and device information from the programmable controller is sequentially stored in the intermediate memory, and the data handling device refers to the device information in the intermediate memory when necessary and uses the device information to perform its own project. In the data transfer method with the programmable controller to be executed,
In the data handling device, a plurality of objects using device information of different device sizes of the programmable controller are assigned to the project to be executed, while the programmable controller required for each object from the plurality of objects before the project execution. number, device number, to create an object table reads the object information such as device size, objects and the object table sorted to the programmable controller by number a and the device number order, sequentially developed with each device unit to the device number order Create a device image table, and create an object image as an intermediate memory that actually stores device information from the object device image table. A process for calculating a pointer indicating the data position in the image image in the object table, setting a plurality of device ranges that can be read and written in one communication over the entire range of the object device image table, Performs pre-processing to write out device information at the head of the device range and the communication size from the head to the devices that communicate with each other as a communication scan table. Once pre-processing is completed, once with the programmable controller Communicate between the programmable controller and the data handling device in accordance with the contents of the communication scan table at a regular or appropriate timing with a communicable information size, and sequentially record device information from the programmable controller in the object image on the other hand Wherein the data handling device, the device information necessary for its own operation, the to capture refers to an object image to compute the position of the communication scan table corresponding to the object image corresponding to the specific device information, the communication The following communication is performed from the scan table position so that the priority order of the objects to be updated can be changed (claim 1). According to this, the data handling device can execute its own operation (project) by referring to the necessary data portion of the intermediate memory when necessary, and the data handling device side synchronizes with the device information acquisition operation from the programmable controller. There is no need to control the application.
Also, once device information is expanded in units of devices, duplicate device information does not need to be acquired even when device information with duplicate objects and bit device information are used together, and communication time Can be shortened. Furthermore, it is possible to preferentially communicate with a specific object that requires high-speed updating.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in a mode in which device information of the programmable controller is displayed on the display device 1. In FIG. 1, a plurality of programmable controllers PLCn, n + 1... Are provided to control the control target device. An arithmetic control device (for example, a personal computer) 2 is connected to the programmable controllers PLCn, n + 1..., And the personal computer 2 is connected to the display device 1. The personal computer 2 includes a display application 3 for displaying device information of the programmable controllers PLCn, n + 1... On the display device 1. As shown in FIG. 1, for example, as shown in FIG. 1, the display application 3 displays device information as a single device information or a device information group including a plurality of device information at a predetermined screen position. It has become. This screen display operation is called a project, and the project is composed of several device information displays as described above. These device information displays are called objects. Here, seven objects 1 to 7 are used to indicate one. There are two projects.
[0007]
Each object 1-7 is given a unique number in the project (screen display operation) in which each object is included, and this is used as display position information as a table number. Each object 1 to 7 has a PLC number n, n + 1... Of the programmable controller PLCn, n + 1..., A device number of the programmable controller PLCn, n + 1..., A table byte size indicating the size of the device. The basic byte unit constituting “1 device” is different.The byte size from the development image offset position when referring to an object image to be described later is the device size), and when the device is a bit device, It has an offset amount from the head of the device in the case of “basic byte unit constituting one device” and an offset position from the head of the object image described later (see FIG. 2).
[0008]
The arithmetic processing device 2 has a preprocessing program 4 for organizing device information used by the objects 1 to 7 before a project is executed (an application for screen display is executed). In the preprocessing program 4, the following processing is performed.
(1) A plurality of object information included in the project is read from the project (screen display application), and stored in the memory area of the arithmetic processing unit 2 as an object table 5 as shown in FIG. The object information of each object 1 to 7 is as described above. Here, the data of the seven objects 1 to 7 are stored in order, and the start address of each object data in the memory area is S1, S2,... S7 in order. ing.
(2) Next, the table data of the object table 5 created in this way is sorted in order of device number by programmable controller number, and the rearranged result is shown in FIG. 3 by the top addresses S1 to S7 of each object data. Thus, the object sort pointer 6 is saved.
(3) Next, referring to the object table 5 according to the contents indicated by the object sort pointer 6, the table on the right side of FIG. 4 is arranged, so that the programmable controllers PLCn, n + 1... According to the contents of the rearranged object table. In addition, the object device image table 7 is created by developing the device numbers in order by device number.
[0009]
Now, since one device is composed of 2 bytes and the object 2 of the table number 2 uses 8 bytes from the device number m of the programmable controller n, the data of 4 devices in 8 bytes / 2 bytes, that is, the device number m to device number m + 3 are used, object number 4 of table number 4 uses device number m + 2 to device number m + 5 in the same manner, object number of table number 6 uses only device number m + 10, and table number 5 The object uses device numbers m + 10 to 5 devices, that is, device numbers m + 14. Further, it is assumed that object 7, object 3, and object 1 of table numbers 7, 3, and 1 are bit devices, respectively, and 1-bit data of bit devices p, p + 4, and p + 5 are used in this order. The bit device refers to a device in units of 1 bit in a 16-bit (2-byte) memory area of the device number p in the programmable controller n, for example, and the bit device offset amount refers to the 16-bit device number p. This is the amount of offset from the first bit.
Since the object image device table 7 is expanded in units of devices, if the contents of the rearranged object table are associated with the object image device table 7, the object data of the table numbers 2 and 4 are shown in FIG. In the object image device table 7, the device numbers m + 2 and m + 3 overlap each other. The object data in the table numbers 6 and 5 overlap with the device number m + 10. This means that if there are a plurality of objects containing overlapping device information in the project, these overlapping device numbers, that is, duplication of communication information, are absorbed by creating this object image device table 7. It is shown that. Further, each bit device of the table numbers 7, 3, and 1 is included in 16 bits of the device number p in which the bit device exists. Will be acquired.
[0010]
(4) Next, an object image 8 for actually storing device information from the programmable controllers n, n + 1... In byte units is created. The object image 8 is created by referring to the above-described object device image table 7 and expanding in byte units corresponding to each device number. That is, the 2-byte area of the object image + 0, + 1 corresponds to the device number m, the 2-byte area of the object image +2, +3 corresponds to the device number m + 1, and so on. Then, the development image offset position of the object data in the object table 5 is calculated from the head of the object image 8 as a pointer, and written in the development image offset positions T1 to T7 of the corresponding object data in the object table 5. For example, since object 2 (table number 2) requires 8 bytes of data from device number m, the offset position is “0” because object image +0 is the head, and object 4 (table number 4) Since 8 bytes of data from the device number m + 2 are required, the offset position is written as “4” since the object image +4 is the head. Similarly, in the objects 5 and 6, the offset position is “12”. In the objects 7, 3, and 1 that are bit devices, the offset position is “22”, and these are written in the corresponding developed image offset positions T5, T6, T7, T3, and T1. In FIG. 2, the written state is expressed by enclosing these numerical values in parentheses.
[0011]
(5) Further, the head device of the object device image table 7 is checked, and from the head device, a device that can be read and written by one communication is searched. A size (collective communication size) for communicating the device group is calculated, and set to the first pointer of the communication scan table 9 together with the previous head communication device information. Next, the next device, which is the last of the previous batch communication size, is set as the top device, and in the same manner as described above, a device that reads and writes data can be searched once, the batch communication size is calculated, and the top communication device information is obtained. At the same time, the process of setting the next pointer of the communication scan table 9 is repeated until the final pointer of the object device image table 7 to create the communication scan table 9.
[0012]
After the above preprocessing is completed by the preprocessing program 4, the arithmetic processing device 2 always communicates with the programmable controllers n, n + 1... From the head according to the contents of the communication scan table 9. Then, the device information from the programmable controllers n, n + 1,... Is sequentially recorded in byte units at positions corresponding to the respective device numbers in the object image 8. On the other hand, the display application 3 converts the device information from the programmable controllers n, n + 1,..., Which is sequentially rewritten as described above, to the data of the developed image offset position of the object table 5 corresponding to the object and the object image as necessary. Using the table data size in FIG. 8, the object image 8 is referred to and screen display is performed. For example, in Project 2, since the developed image offset position is “0” and the table byte size is “8”, data of 8 bytes (from object image +7) to the beginning of object image 8 (object image +0) is acquired. indicate. In this way, the display application 3 can exchange device information asynchronously with a communication system that sequentially rewrites device information, so communication control is extremely simple. Further, even when overlapping device information is handled in each object, such as the object 2 and the object 4, such overlapping device information is eliminated by expanding the device unit, and device information is acquired redundantly. There is no need, and the communication data size can be reduced.
[0013]
The object image 8 is sequentially rewritten based on the communication scan table 9. For example, the object image +0 to +8 in the middle of the object image 8 corresponding to the device numbers m to m + 3 used in the object 2 (for example, the object image +5). When the object 2 refers to the object image 8 when the rewriting is performed, the object image +0 to +5 is new data, but the object image +6 and later are the previous data. If this is acquired as it is, it is not preferable because new and old device information is mixedly acquired in one object. In such a case, data of object images +0 to +8 is not acquired. Specifically, count data that is counted every time all data of the object image 8 is rewritten is added to each device information written in the data area for each byte of the object image 8, and the count data is If the target data range of the object image 8 to be captured matches, the device information is acquired, and if it does not match, the device information is not acquired.
[0015]
【The invention's effect】
As described above, in the present invention, the data handling device can execute the project by referring to the necessary data portion of the intermediate memory when necessary, and it is necessary to synchronize the application on the data handling device side with the device information acquisition operation from the programmable controller. There is no simple communication control. Also, by deploying device information in units of devices, it is not necessary to obtain duplicate device information even when device information with overlapping objects or bit device information is used together. There is an advantage that the data communication time can be shortened.
In the above-described embodiment, the communication scan table is read in order from the head and data communication is performed. However, when an immediate display update of specific device information is desired, an object image corresponding to the device information is displayed. It is only necessary to calculate the position of the corresponding communication scan table and perform the next communication from the position of the communication scan table, and give priority to objects that need to be weighted and updated at high speed. Can communicate.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an overall configuration of the present invention.
FIG. 2 is a diagram illustrating an object table.
FIG. 3 is an explanatory diagram of an object sort pointer.
FIG. 4 is an explanatory diagram of an object device image table.
FIG. 5 is an explanatory diagram of an object image.
FIG. 6 is an explanatory diagram of a communication scan table.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Display apparatus 2 Arithmetic control apparatus 3 Display application 5 Object table 7 Object device image table 8 Object image 9 Communication scan table PLCn, PLCn + 1 Programmable controller

Claims (1)

This is a method for transferring data between a programmable controller and an external data handling device such as a display device, and an intermediate memory for storing device information corresponding to the device number of the programmable controller is provided. The device information from the programmable controller is sequentially stored in the intermediate memory, and the data handling device refers to the device information in the intermediate memory when necessary, and uses the device information to execute the project with the programmable controller. In the transfer system,
While the data handling device is assigned multiple objects that use device information of different device sizes of the programmable controller to the project to be executed,
Before running the project,
(1) Read object information such as the programmable controller number, device number, and device size required for each object from multiple objects, create an object table,
(2) Sort the object table by programmable controller number and in device number order,
(3) to create an object device image table are sequentially deployed in each device unit to the device number order,
(4) An object image as an intermediate memory for actually storing device information is created from the object device image table, and a process for calculating a pointer indicating a data position in the object image is performed in the object table.
(5) A device that sets a plurality of device ranges that can be read and written in one communication over the entire range of the object device image table, and communicates collectively from the head of each device range and the device information. Pre-processing to write out the communication size up to the communication scan table,
After the preprocessing is completed, with the information size that can be communicated with the programmable controller at a time, according to the contents of the communication scan table at any time or at an appropriate timing, communication is performed between the programmable controller and the data handling device,
While sequentially recording device information from the programmable controller in the object image,
The data handling device captures device information necessary for its own operation with reference to the object image ,
The communication scan table position corresponding to the object image corresponding to specific device information is calculated, the next communication is performed from the communication scan table position, and the priority order of objects to be updated can be changed. Data exchange with a programmable controller.

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